{"id":"CVE-2026-55159","summary":"luci-app-adblock-fast: Delegated `luci-app-adblock-fast` users can reach root command execution by injecting newline-separated cron entries","details":"luci-app-adblock-fast a WebUI for fast, lightweight DNS-based ad-blocker for OpenWrt that works with dnsmasq, smartdns, or unbound. Prior to 1.2.4-2, the luci.adblock-fast.setCronEntry RPC method accepts an entry argument containing carriage-return or line-feed characters and serializes it into /etc/crontabs/root as though it were one logical line. An authenticated delegated user with the luci-app-adblock-fast write ACL can therefore create an additional physical root cron entry through applications/luci-app-adblock-fast/root/usr/share/rpcd/ucode/luci.adblock-fast, resulting in persistent command execution as UID 0 when cron runs. The issue is not demonstrated for unauthenticated callers or users without the component write ACL. This vulnerability is fixed in 1.2.4-2.","aliases":["GHSA-ggpf-xrph-wg5v"],"modified":"2026-09-26T03:30:18.725144581Z","published":"2026-09-21T19:24:03.581Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-93"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55159.json","unresolved_ranges":[{"source":"AFFECTED_FIELD","extracted_events":[{"fixed":"1.2.4-2"}]}]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55159.json"},{"type":"ADVISORY","url":"https://github.com/openwrt/luci/security/advisories/GHSA-ggpf-xrph-wg5v"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55159"},{"type":"FIX","url":"https://github.com/openwrt/luci/commit/9ccd99b5898457e5ef39dc21aea226d7fb6e5c7e"},{"type":"FIX","url":"https://github.com/openwrt/luci/commit/f67461fd0255bf992b2b559c22ec288067f2f9da"},{"type":"FIX","url":"https://github.com/openwrt/luci/pull/8705"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/openwrt/luci","events":[{"introduced":"0"},{"fixed":"9ccd99b5898457e5ef39dc21aea226d7fb6e5c7e"},{"fixed":"f67461fd0255bf992b2b559c22ec288067f2f9da"}],"database_specific":{"source":"REFERENCES"}}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55159.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}